Field of the Invention
The invention relates to a module board, for instance for memory components of computer systems, in the form of a circuit board, including conductor tracks, first terminal points for at least one first integrated circuit, and external terminals for input/output signals, the conductor tracks having disconnectable connecting elements for connection between the external terminals and the first terminal points.
Such a module board is known from U.S. Pat. No. 4,656,605.
Memory components in computer systems are being used less and less in the form of single components and more in the form of memory module boards, that is a combination of memory components which are already mounted on a standardized solderable or plug-in circuit board. One example is the SIMM (single in-line memory module) board, which is defined by the JEDEC standard. FIG. 1 shows one such standard DRAM module board which is discussed in detail below and is of the kind described in U.S. Pat. No. 4,656,605.
Those modules can easily be used as memory media in the most various kinds of systems. However, interface problems often arise, for example with regard to whether the system bus is made with TTL or ECL technology; which bus lines are electrically terminated; and so forth. Due to those various interface configurations, complicated additional circuits, such as driver components and error correction circuits, must be used in the computer system. For reasons of both cost and standardization, it is not generally possible for all of the existing interfaces to already be provided in the individual components.
In the prior art, so-called "intelligent" memory module boards are also known, wherein the additional logic required in the memory is implemented in additional integrated circuits on the module board. The additional integrated circuits communicate with the system bus and monitor the flow of data to be written in or read out.
Those so-called "intelligent" module boards can therefore be used in many system configurations, since the additional logic can easily be modified by being programmed to suit existing system requirements. However, that proves to be expensive for relatively simple systems where the complicated additional logic is not always absolutely necessary, and where the memory access speed is not as critical as in mainframes.